He actually picked bad numbers. That is a losing bet even on average. You can see that pretty easily by just assuming you get exactly the opposite result each time. 1.5 * 0.6 = 0.9, so no matter how you start, you're behind with an equal number of wins and losses. Naively, you might think "50% is more than 40%," but that isn't how percentages work. You need win and loss proportions with a geometric average of 1 for a breakeven expectation (percentages are multiplicative, not additive). In this case, 3/2 and 2/3 is what you'd need.
This happens to not show after only 100 trials just because some tiny number of people get really lucky and draw up the ensemble average, but if you keep going, somewhere between 200 and 500 trials, the ensemble average pretty quickly drops below the starting average wealth and stays there, asymptotically approaching 0.
This happens to not show after only 100 trials just because some tiny number of people get really lucky and draw up the ensemble average, but if you keep going, somewhere between 200 and 500 trials, the ensemble average pretty quickly drops below the starting average wealth and stays there, asymptotically approaching 0.